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From artificial heart valves to cell transplants, new treatments for cardiovascular disease are being developed every day. To model how the heart works, researchers need a reliable way to observe the heart in action. Animal experiments, computer models, and various laboratory simulators made with dead heart tissue all offer different views, but these approaches can be expensive, lack complexity, or have a limited shelf life. There is likely to be.
To play with the heart, scientists have developed a beating biorobotic replica that can simulate the workings of both healthy and diseased organs. The simulator combines pig heart tissue with soft robotic muscles and is described in two of his recent studies.
“Imagine a heart beating on a bench,” says Ellen Roche, a biomedical engineer at the Massachusetts Institute of Technology and lead author of the study. The simulator pumps out a clear liquid instead of blood and is connected to equipment that measures things like blood flow and blood pressure. It is also customizable. Users can change heart rate, blood pressure, and other parameters and monitor how these changes affect heart function in real time through an internal camera.
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This simulator accurately reproduces the way blood flows through the heart. This was not possible with existing benchtop simulators that use dead heart tissue. Instead, using living pig heart tissue powered by robotics gave the Roche team more control. (Pig hearts are similar in size and arrangement to human hearts and are often used in research.) The new hybrid simulators can also last longer than living organs used alone. A pig’s heart, on the other hand, is connected to a heart pump. The Roche team was able to keep the synthetic muscles in the simulator moving for months, whereas they could only keep the heart beating for a few hours in the lab. The researchers have not yet determined the exact limits of the simulator. “To see exactly how many cycles these products will last, we need to perform robust shelf-life fatigue testing,” says Roche.
When modeling blood flow through the heart, the left and right sides of the organ pose unique challenges. “We need a very customized model,” says Roche. The researchers worked on the left side first, focusing on the mitral valve, which controls flow between the left atrium and ventricle (the upper and lower chambers of the heart). They recreated the system’s healthy behavior before modeling a condition called mitral regurgitation, in which the valve becomes leaky. To demonstrate that this model could be used as an accurate simulation, the team had a cardiac surgeon modify the valve with three different surgical interventions. These results are described in one of his two recent studies published Wednesday. device.
“In order to pump blood through the body at very high pressures and flow rates, we need to create a very complex pumping action,” says Clara Park, Ph.D., co-author of both studies. student in MIT’s Roche lab
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The team then modeled the mechanics of the right side of the heart. “The right heart is more of a thin, weak muscle that doesn’t pump as hard,” Park says. A suitable cardiac simulator can reproduce both healthy and abnormal function. These results are described in the team’s other recent study published last month. Nature cardiovascular research.
Sara Vigmostad, a biomedical engineer at the University of Iowa who was not involved in the paper, believes these simulators could be valuable for surgical planning, training, and educational purposes. “We can also imagine its value in testing new interventions designed to treat mitral regurgitation and other valve diseases,” she says. The ability to “tune” the heart to reproduce different diseases could also be very useful for research, she added.
While biorobotic approaches rely on tissue from living animals, Roche dreams of an artificial heart that is completely 3D printed. Such organs could become even more customizable. It can also be used to create patient-specific models that allow people undergoing treatment to see a replica of their own beating heart, which could also help guide doctors’ decisions. “We are moving to a fully synthetic model. [and] “Multi-material printing,” she says, would require replicating the heart tissue itself in the lab. “There’s a lot of work in progress.”
